Rivers 4 Lesson - Earth Science › Resources › Rivers_4 Lesson.pdfRivers Instructional Case: A...

R ivers Instruct ional Case: A ser ies of s tudent-centeredsc ience lessons

Lesson4

SuggestedTimeline50minutes

Materials

• 1Streamtableforeachstation• 1Calculatorforeachstation• Approximately3lbofsandand100gofclayforeachstation

• 1Stopwatchperstation• 1-16ozplasticcupwithsmall(1/16”to1/8”diameterhole)perstation

• 1“flood”cupforeachstation(16oz.plasticcupwithlargerhole,~1/4”)

• 1bucketperstationforcatchingwaterandstoringstationmaterials

• 1bucketperstationforstudentsrinsingtheirhands

• 2rulersorpainter’ssticksperstationtosecurewatercups

• 2-31-2”tallplasticrectangularblocksforstackingpiecesperstationtoadjustangleofstreamtables

• 1rollofmaskingtape• 1bagpiecesorplasticcubesrepresentingmodelbuildings

StreamTableLab

SummaryStudentswillrecreateamodelofariversysteminatabletopexperiment.Thelessonadvancesstudents’qualitativeunderstandingofhowriversshapetheEarth’ssurfacewhileexplicitlyprovidingopportunitiestodeveloptheirsciencepracticessuchasobservation,modelingandexperimentation.Studentswillgaintheknowledgethattheangleoftheslope(gradient)andvolumeofwateraffectstheshapeoftheriverandobservethesurfacefeaturesthatresult.

Objective

• Studentswillinvestigatestreamtablestolearnaboutriversystemsandhowrivererosionanddepositionshapesthelandscape.

• Identifyfactors(e.g.slope,rateofwaterflow)thataffectariver’sabilitytoerodelandandcarrysediment.

• Studentsknowriversandstreamsaredynamicsystemsthaterode,transportsediment,changecourseandfloodtheirbanksinnaturalrecurringpatterns.

TeacherBackgroundKnowledgeRiversaredynamicsystemsthatareconstantlychanging.Inthisactivity,studentswillmodeltheevolutionofriversbychangingavarietyofvariablessuchasthesteepnessoftheterrainandthewaterflowrate.Riverstransportsedimentinaprocessknownaserosion.Inthisactivity,studentscanobservethetransportofsedimentdownstreambytheflowofwater.Inaddition,studentswillbeabletoobservethedepositionofsedimentwherethestreamemptiesintotheopenpartofthestreamtable.Thedepositionofsedimentatthemouthoftheriverinthestreamtableisanalogoustoanaturalriveremptyingintotheoceanoravalleyformingariverdeltaoralluvialfan,respectively.Sincethemouthofthestreaminthetableisnotsubmerged,thesedimentdepositwouldbemoreanalogoustoanalluvialfan(ratherthanadelta).

Page2of7

Lesson4 StreamTableLab

Prep

1. Positionthespillbucketunderthebottomholeinstreamtable.

2. Pourthepre-measuredclayintothesand.Mixtheclay,sand,andsomewatertogether.Thesedimentshouldsticktogetherbutnotbetoowatery.

3. Smooththesandintoaniceshelf

(seepictureabove).4. Tapethepainter’sstickalongthe

topedgeofthestreamtable.Makesurethecupwillbalancewiththecup’sdrainholepositionedbetweenthepaintstickandthestreamtable.

5. Carefullyplacetheplasticrectangularblocksunderthebackofthestreamtable.

TeacherBackgroundKnowledge(continued)Althoughitisnotpossibletoobservethespontaneousdevelopmentofameanderinthestreamtable,itissometimespossibletoobserveameanderifachannelwithasharpbendiscutintothesandbeforeinitiatingtheflowofwater.Studentscanexperimentwithmeandersaspartoftheirinvestigations.InPartIofthisactivity,studentswillbegiventheopportunitytochangetheangleofthestreamtableandmakeobservationsaboutthedifferencesthattheyobserve.Thestreamgradientistheratioofthechangeinelevationwiththedistancethattheriverflows.Forexample,sayingastreamhasagradientof1m/km(“onemeterperkilometer”)meansthattheelevationofthesurfaceoftheriverdecreases1mforeverykilometerthattheriverflows.Riverslocatedinmountainousregionswouldhaveahighgradient(largerchangeinelevationoverdistance)andahigherwatervelocity.Thishigherwatervelocityallowstherivertocarrymoresediment.Likewise,streamswithalowstreamgradientwouldhavealowerwatervelocityandwouldcarrylesssediment.

Lesson4 StreamTableLab

Standards12

NGSSPerformanceExpectations:ThislessonsupportsstudentsinprogressingtowardtheNGSSPerformanceExpectation.MS-ESS2-1.DevelopamodeltodescribethecyclingofEarth'smaterialsandtheflowofenergythatdrivesthisprocess.[ClarificationStatement:Emphasisisontheprocessesofmelting,crystallization,weathering,deformation,andsedimentation,whichacttogethertoformmineralsandrocksthroughthecyclingofEarth’smaterials.] AssessmentBoundaries:Assessmentdoesnotincludetheidentificationandnamingofminerals.Inthislesson…ScienceandEngineeringPractices DisciplinaryCoreIdeas CrossCuttingConcepts

PlanningandCarryingOutInvestigationsStudentswillconductaninvestigationtoobservevariousfactorsthataffectariver’sabilitytoerodelandandcarrysediment.Studentswillhavetheopportunitytorevisetheexperimentaldesigntolookatslopeandrateofwaterflow.Theobservationaldatagatheredwillsupportthestudents’claimsabouterosionandsedimenttransportation.

ESS2.A:Earth’sMaterialsandSystemsStudentslearnabouterosionandhowthiscontributestophysicalchangesontheEarth’ssurface.Erosionmaybecausedbynaturalforcessuchaswater,rain,waves,andothersurfaceactivities.Studentsareparticularlylookingatthelandformitselfandtheamountofwaterwithinthesystem.

SystemsandSystemModelsStudentswillsetupariversystemcontainingwater,sediment(clayandsand),othervariablessuchasslope.Studentswillevaluatethemodelunderdifferentcircumstancesandobservesedimentanderosionpatterns.

Inthislesson…CCSSMathematics CCSSEnglish-LanguageArtsCCSS.MATH.CONTENT.7.RP.A.1Asmathematicalextensions,studentscancomputeunitratesassociatedwithratiosoffractions,includingratiosoflengths,areasandotherquantitiesmeasuredinlikeordifferentunits.Studentscantaketheamountofwaterovertimeandcalculatethewaterflowrate.Studentscanalsomeasurethesizeofthealluvialfanorestimatetheamountofsedimentthatgetsdepositedintothealluvialfan.

CCSS.ELA-LITERACY.RST.6-8.3Studentswillfollowpreciselyamultistepprocedureofconstructingamodelofariversystemandthenwhencarryingoutexperiments,theywillmakeobservationsandwillalsotakemeasurements.

1NGSSLeadStates.2013.NextGenerationScienceStandards:ForStates,ByStates.Washington,D.C.:TheNationalAcademiesPress.2NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficersTitle:CommonCoreStateStandards(insertspecificcontentareaifyouareusingonlyone)Publisher:NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficers,WashingtonD.C.CopyrightDate:2010

Page4of7

Lesson4 StreamTableLab

Lesson

1. ActivatePriorKnowledgea. Personalexperience-takeafewexamplesofrivers(e.g.,localrivers,famousrivers,historical

examples),allowstudentstosharepersonalexamplesi. SeeSanFranciscoBayDeltamodel,e.g.,

http://en.wikipedia.org/wiki/U.S._Army_Corps_of_Engineers_Bay_Modelb. Erosion/depositionarefamiliartermsfrompreviouslessonsc. Warm-upprompt:whatisanexampleoferosioncausedbymovingwater?d. Floodpics/videotoencouragediscussion–anexampleistheScienceFridayvideo,“Recipe

foraRiver”.2. TeacherDemonstration:Showstudentshowtosetupstreamtables.Demonstratehowtosculptthe

sand,setupthewatersource,settheangleofthestreamtableandwhattolookforintheirobservations.

3. LabProcedureRoles:Assignrolestoeachstudentingroup

Pourer:isinchargeofthewater SandSculptor:isinchargeofthesand DataRecorder:recordsalldata MaterialsManager:collectsandreturnsallmaterials

Part1:GradientandWaterSpeedQuestion:Howwillincreasingthegradient(slope)affectthewaterspeed?

1. Havestudentswriteahypothesis:2. Usetheemptystreamtable.3. Havethepourerfillthe“Normal”flowcupwithwaterandholdfingerontheholeuntilreadyfor

release.4. Thematerialsmanagerwilltimehowlongittakesforallofthewatertoreachthecatchbucketat

theendofthestreamtable.5. Repeatthree(3)timesandfindtheaverageflowtimeforone(1)plasticblockunderthestream

table.6. Placeanotherplasticblockunderthestreamtableandrepeatthemeasurementofwaterspeed

forthestreamtablewithtwo(2)plasticblocks.Findtheaverageofthree(3)trials.7. Iftimeallows,usethree(3)plasticblocks.8. HavestudentsusetheirdatatomakeaCERaboutgradientandwaterspeed.

PartII:WaterSpeedandSedimentLoad

1. Havethestudentschangetoanewrolesothateveryonegetstoexperienceeachrole.2. Usingthestreamtablewithsoil,havestudentssetone(1)plasticblockunderthestreamtableto

simulatelowgradient,lowwaterspeed.3. Usingthe“Normal”flowcup,studentswillobservetheerosionanddepositionofsediments

causedbyalowgradientflow.4. Drawtheresultsofthe“Normal”flowofwaterdownthestreamtable.Paycloseattentiontothe

erosionpatternsandthedeposition.Lookcloselyatthesizeofthesoilparticlesthatarebeingerodedanddeposited.

5. Havethesandsculptorresetthesandtoitsoriginalposition.

Page5of7

Lesson4 StreamTableLab

6. Repeattheexperimentwithtwo(3)plasticblocksunderthestreamtable.Thiswillsimulatehighgradient,highgradientandhighwaterspeed.

7. Drawtheresultsoftheflowonthestreamtable.

PartIII:ChannelShapeandPatternofDeposition

1.Havethestudentschangerolesagain.2.SandSculptorwillresetthesoilinthestreamtable.Insteadofmakingitsmoothandevenly

spread,cutashallowchannelstraightfromthewatersourcetothedrainhole.3.Usingthe“Normal”flowcup.Runtheexperiment.4.Drawtheresultsofhavingastraightriverchannel.Besuretopayattentiontoareasoferosion

andareasofdepositionaswellasthesizeofthesoilparticles.5.Repeattheexperimentexcept,thistimemakethechannelwindbackandforthacrossthestream

table.6.Drawtheresultsofhavingawindingriverchannel.Besuretopayattentiontoareasoferosion

anddeposition,aswellasthesizeofthesoilparticles.

PartIV:FloodingandPatternofDeposition

1.Havestudentschangeroles.2.SandSculptorwillresetthesoilinthestreamtablecreatingthestraightchannel.3.Usingthe“Flood”flowcup.Runtheexperiment.4.Drawtheresultsofhavingastraightriverchannel.Besuretopayattentiontoareasoferosionandareasofdepositionaswellasthesizeofthesoilparticles.

5.Repeattheexperimentexcept,thistimemakethechannelwindbackandforthacrossthestreamtable.

6.Drawtheresultsofhavingawindingriverchannel.Besuretopayattentiontoareasoferosionanddeposition,aswellasthesizeofthesoilparticles.

7.Comparetheresultsofthe“Flood”flowwiththe“Normal”flowinPartIIIoftheexperiment.WholeClass/SmallGroupCriticalThinkingQuestions

1. Whatisthepatternoferosionthatyourgroupobserved?2. Wheredoesthesedimentcomefrom?Whereisthesedimentbeingdeposited?3. Whatangleofflowcarriedthegreatestsedimentload?4. Whereismostofthesedimentloaddeposited?5. Doesthechannelalwaysstayinthesameplaceasthewaterisflowing?Whathappenstothe

channelovertime?6. Howdidtheflood(changingflowvolume)affecttheexperiment?7. Describetheflowofthewaterandhowthesedimentloadiscarried.8. Ifyourgroupexperimentedwithmeanders,whathappenedtothemeandersovertime?Where

didtheerosionoccurinthemeanders?EvaluatetheModel

1. Limitationsofthemodelversusanactualriver2. Revisingthemodeltoincorporateotherfactors

Page6of7

Lesson4 StreamTableLab

LessononC-E-R1. DiscusstheC-E-RFrameworkwiththeclassbyaskingstudentstheirdefinitionsofclaim,evidenceand

reasoningis.2. UsingtheAudiCommercial:MyDadisanAlientointroducestudentstothecomponentsofan

explanationbyaskingthemtoidentifytheclaim,theevidence,andthereasoning–orrule–thatconnectstheevidencetothelittlegirl'sclaimthatherdadisaspacealien.

3. Claim-Evidence-Reasoning(C-E-R)–Day24. TeacherintroducesclasstoC-E-RframeworkandgivesaexamplesthroughaYouTubecommercialon

“MyDadisanAlien”Then,studentsdiscussthequestion,claim,evidenceandreasoningthattheyexperiencedwithalloftheactivitiesinthattheyhaveparticipatedintocomeupwithascientificexplanation.AudiCommercial:MyDad’sanAlienhttp://www.youtube.com/watch?v=WQTsue0lKBkClaim:AstatementorconclusionthatanswersthequestionaskedortheproblemposedEvidence:Scientificdatathatsupportstheclaim.Thedataneedstobeappropriateandsufficienttosupporttheclaim.Reasoning:Ajustificationthatconnectstheevidencetotheclaim.Itshowswhydatacountsasevidencebyusingappropriateandsufficientscientificprinciples.

5. DistributetheRiverErosionC-E-Rworksheet.6. Next,wecanaskanddiscusswithstudents:

a. Whatdatadotheyneed?b. Howdoestheangleofflowaffectrivererosion?c. Andhowdidtheycollectthatdata?d. Howdidtheyinvestigate?

7. Studentswillneedtodeterminefromtheirobservations,dataandprintresourceshowangleofflowaffectserosion.Reviewwithstudentstheinvestigationconductedandnow,theycandetermineanexplanation.

Askstudents-whatdoesagoodexplanationlooklike?Constructaposterwiththestudentthatlookslikethis:8. Inpairs,letstudentscircletheclaim,evidenceandreasoningintheRiverErosionC-E-Rworksheet.

Page7of7

Lesson4 StreamTableLab

PotentialPitfallsThisactivityisamodelofhowriversmayevolveovertime.Asaninstructionalmodel,ithasitslimitationsandmayvaryfromwhatactuallyoccursinnature.Forexample,itmaybeverydifficulttoobservethedevelopmentofameanderandotherfeaturesinthestreamtable.Studentsshouldalsobemindfulthatrealriversevolveovergeologictimewhereasthisactivityacceleratesthetimescaletotheclasslabtime.Lastlystudentsmaynotbeabletograspthequantitativeconceptofthestreamgradient,butcanqualitativelyunderstandthattheangleofthestreamtableisanalogoustothesteepnessofthelandscape.Thissteepnessofthestreamtable(landscape)affectstheflowvelocityofthewater,theamountofsedimentcarriedbythestreamandtheevolutionoftheriver.

DifferentiationELDModifications

a. Level1:“Pointto…”;“Showme…”;PoseYes/Noquestionsb. Level2:Either/OrQuestions;1-WordAnswerPromptsi.e.“Whatisthiscalled?”c. Level3:SentenceFrames;Promptstodescribe,compare,sharetheirobservationsd. Level4:“Whatwouldhappenif…”;Compare/Contrasti.e.lowervs.higherangleofflow